Every so often, my video card refuses to go to its proper speeds when I attempt to play a game. However, I can exit the game, or alt tab from it, load a youtube video, and it goes back up to the proper clock speed. For some reason it will change for youtube but not for my game. Rebooting fixes it, but I don't like having to reboot everytime it happens.

The problem typically starts after browsing youtube or watching videos in general. I can get around the issue by running a youtube video in the background and pausing it, but I'd much rather fix the problem. I've tried leaving hardware acceleration disabled, no fix.

I've tried using MSI afterburner to stop the 2D clock altogether, but it doesn't work. I've also tried updating drivers after using driver sweeper in safe mode to remove the old ones. It still happens. Any ideas?

It may be a driver issue as i found i have to run GPUZ on my system in order for my secondary GPU to report any speeds, temperatures or fan control. Once i run GPUZ and leave it running in the background i get full normal control of it again. Perhaps you should try this yourself?

Try a couple of different Drivers to find one that works properly.....had this annoyance when I was running 3 x 280's..only mine wouldn't downclock to 2D mode...once I found a Driver whereby they upclocked / downclocked properly I kept it!!

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Introducing me n my OCD to Watercooling, is like taking an Alcoholic to an "all you can drink" Beach Bar in Mexico

^^^Glad to hear it...
Remember, in Full Performance Mode GPU's will not downclock to 2D Mode (higher temps)..as I said, try a few different Drivers until you find one where "Adaptive Mode" works properly.
With my 280's, I recall all of the 19x.xx series of Driers FUBAR my Adaptive Mode (stuck to 186.xx for quite awhile)....
..btw..welcome to HWC !

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Introducing me n my OCD to Watercooling, is like taking an Alcoholic to an "all you can drink" Beach Bar in Mexico